Gene links abuse to criminality

A scientific study of New Zealanders has identified a gene which increases the risk of men who were abused as children acting violently as adults.

If verified, the discovery could result in a test to help identify which mistreated children could turn into criminals.

The gene, which comes in two versions, produces an enzyme that regulates chemical messengers in the brain.

Of the men who had suffered physical, sexual or emotional abuse as children, about 12 per cent had a genetic variation associated with low-level activity of the enzyme. Yet they were responsible for 44 per cent of the violent crimes committed by this group.

"They're doing four times their share of rape, robbery and assault," team leader, Dr Terrie Moffitt, of King's College, London, told the journal Science, where the research was published yesterday.

Having a high-activity version of the gene, on the other hand, appeared to help protect people from the trauma of a troubled childhood, reducing their chances of anti-social behaviour later in life.

The research by a New Zealand, British and United States team was based on 442 men of caucasian background studied for 26 years from birth.

About 36 per cent had been mistreated, 8 per cent severely.

Their level of adult anti-social behaviour was gauged from their misconduct as adolescents, convictions for violent crime, a psychological assessment and the impressions of someone who knew them well.

Until the gene discovery had been replicated, it would be premature to speculate whether it would lead to new treatments or tests, the team said.

Professor Kim Oates, of the Children's Hospital, Westmead, said the finding was a small step on the way to understanding child abuse.

"It is such a complex problem that the answer isn't a simple genetic explanation."